Automatic safety device for elevators.



PATEN'I'ED JUNE 13, 1905.

J. A. GRAY. AUTOMATIC SAFETY DEVICE EUR ELEVATORS.

APPLICATION FILED PR. 4. MODEL. A 27 190 ,fle l No. 792,2os.

UNITED STATES i Patented June 13, 1905.

PATENT OFFICE.

.AUTOMATIC sAFgTYpEvlcE Fon ELEvAToFzsl SPECIFICATION forming part ofLetters Patent No. 792,208, dated June 13, 1905. Applicationiiled April2l7, 1904. Serial No. 205,101. (Model.)

To all wil/0m, t may concern:

Be it known that I, JOHN A. GRAY, a citizen of the United States,residing at Allegheny, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in AutomaticSafety Devices for Elevators, of which improvement the following is aspecification.

This invention relates to an improved automatic safety-clutch forelevator-cars, the object being to provide a self-acting device simplein construction that may be arranged in connection with any style of anelevator-car, that will instantaneously stop the same should thehoisting-rope break; and it consists in surrounding the car with aspring-actuated frame carrying clamping-levers adapted to engage withthe guide-rails in the elevator shaft or well and hold said carstationary, together with the certain details of construction andcombination of parts, as will be fully described hereinafter.

In the accompanying drawings, Figure 1 is a front elevation of anelevator-car provided with my improved automatic safety-clutch, the samebeing constructed and arranged in accordance with my invention. Fig. 2is a sectional plan view of the same, the said section being' taken onthe line X X of Fig. 1. Fig. 3 is a side elevation of the car anddevice. Fig. 4 is a plan view of the top portion of the framesurrounding the elevator-car. Fig. 5 is a sectional plan view of thebase ot the same.

To put my invention into practice, and thereby provide means forinstantly stopping an elevator car should the rope accidentally break,the said car beingl suitably mounted within an elevator-shaft 3 andoperated between vertically-arranged guides 2, to which said car isloosely attached by shoes 4 and elevated and lowered by a rope 5 passingover sheaves 8, mounted on supports at the top of the shaft in a mannerwell known in the art, I construct a frame about the said car 1,consisting of a platform or base portion 9, rectangular in form, to theends of which vertical beams 1l are firmly connected, the said beamsextending upward above the top level of the car 1 and fitted with across-piece 13.

This cross-piece is formed with a central oriiice 15, through which theoperating-rope 5 passes, and at either side of said orifice withopenings 14., through which two stout guidepins 16 operate, the saidpins being firmly attached to the top of the elevator-car 1 and aresurrounded by spiral springs 17', which bear against the cross-bar 13and tend to thrust the frame upward.

Arranged at each end of the base portion 9 of the frame and at each sideof the two guides 2 are clamp-levers, each of which consists of a strongmetal bar 17, pivoted by a bolt 18 in a position that will permit theinner end to take a frictional hold upon one of said guides 2, and theouter end formed with a slot 21, which by means of a pin 20 aords ameans of connection with the base 12 of the car 1 in a manner that whenthe said car is given a slight upward movement the outer ends of theclamp-bars are carried upward, thereby removing the inner or clamp endsaway from the guide-rails 2, the inner ends of the clampbars beingcurved on lines eccentric to their pivotal points.

In operation the car 1 is suspended and operated by the rope 5, thesprings 17 being compressed by the weight of the frame. Should the rope5 accidentally break, the car 1 drops by gravity and takes the positionshown in the several views of the drawings, the movement of the framebeing retarded for an instant, caused by the action of the springs 17',increasing the space between the said car and the top of the frame.During this momentary stop the outer ends of the clamps 17 aredepressed, causing the inner extremities of the same to engage with theguide-rails 2, and it is obvious that by this construction andarrangement the greater the weight of the car and its contents thegreater will be the hold of the clamps upon the guiderails, and theweight of the car Will therefore render the car immovable. To releasethe car from this position, it is only necessary to connect the car 1 tothe rope 5 and elevate the said car slightly or to the position shown indotted lines at Fig. 1 of the drawings. This movement of the car withinthe frame carries the outer ends of the clamp-levers 17 upward,separating the same from contact with the guide-rails 2.

It will be seen by the above description, taken in connection with theaccompanying drawings, that the operation of stopping the car isinstantaneous and automatic and will eifectually prevent the car fromfalling in case of an accident to the lifting-rope 5.

It will be readily understood that by slight modications this device maybe adapted for use upon the cars of inclined railWays,Where the saidcars are hauled up and let down steep grades by the use of cables, inwhich case the clamps would engage with the rails of the track, and itis also obvious that various slight modifications and changes may bemade in the details of construction without departing from the spirit ofthe invention. Therefore I do not wish to confine myself to that shownand described.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

1. An automatic safety device for elevators comprising in combinationwith an elevatorcar, a movable frame, springs arranged on top of the carbetween the ear and the movable frame, slotted clutch-bars mounted onsaid frame, pins on the car working in the slots in said clutch-bars,the inner clutching surface of said clutch-bars being formed eccentricto the pivotal axis of the same.

2. An automatic safety device for elevatorcars, comprising the frame inwhich the said car is suspended, the guide-pins 16 connecting the top ofthe car with the frame, the interposed springs v17 the clamp-barsattached to the frame and arranged in pairs at opposite sides of theguide-rails 2, each of which consists of a bar 17, pivoted bya holt 18,and provided with a Slot 21, whereby connection is made with the car bymeans of a suitable pin 20, all arranged and combined for service,substantially as and for the purpose described.

In testimony whereof l have hereunto signed my name in the presence oftwo subscribing witnesses.

JOHN A. GRAY. in presence of# C. C. LEE, C. A. RoBB.

